This is a knife bayonet manufactured to fit the first bolt-action magazine rifle adopted by the US Military. The rifle was based on the Danish Krag while the bayonet was based on - and virtually identical to - the Swiss Schmidt-Rubin Model 1889. This bayonet - and rifle - saw most of its action during the Spanish-American War and the ensuing action in Cuba.
They are very well made, all steel, with wood grips. The hilt configuration is a "bird's head" pommel with the standard push-button/integral spring latch, steel crossguard; grips are wood and held on by flush-mounted rivets.
The blade is also well made: steel, single-fullered (both sides), single-cutting-edge with short false-edge towards the tip. Blades are marked US on one side of the ricasso, with a date between 1894 and 1902 on the opposite side.

Scabbards come in two basic configurations, both sheet-rolled steel and blued. The difference is in the belt attaching hook or loop, but all types swiveled side-to-side (front-to-back when on a side-belt).